This document provides information about the components and operation of a darkroom for processing radiographic films. It discusses that a darkroom is needed to safely handle films without light exposure. The key components of a darkroom include storage shelves, workbenches, processing tanks, lights, and ventilation. Different types of entrances like single door, double door, and revolving doors are described. The document also explains the principles and proper use of safelights for illumination and white lights for maintenance. Finally, it provides an overview of the chemistry and stages involved in automatic film processing, including development, fixing, washing and drying.

1. Dr. Soumitra Halder
Dept of Radio-diagnosis
Medical College,Kolkata
DarkRoom

2.  It is a place where the necessary
handling and the processing of the
film can be carried out safely and
efficiently without the hazard of
producing film fogging.
 It must exclude all outside light
and provide “SAFE” artificial
light
Dark Room

3. BASIC COMPONENTS OF
DARKROOM
STORAGE SHELVES
WORKBENCH

4. • Processing Tanks
• Warning Light outside room
• Lockable Door
• Film Bin
• Loading Bench
• Pass Box
• Lights safelight/whitelight
• Wash basin
• Drying cabinet
• Hangers for suspending films
Equipments in Darkroom

5. Location
 Centrally sited served with hatch's from
adjacent imaging rooms
 Away from hot or damp areas
 Power And water supply accessibility
 Near to viewing/reporting room
 Avoid windows
Dark Room

6. Room character
• Min 10m sq.
• Height 2.5 – 3m
Dark Room
Walls /ceiling
• Wall being Plastered/ thick wall
• Light colored to reflect the light-as to use lesser
safelight.

7. Floor
• Non-porous
• Non-slip
• Durable and easy maintaince
Dark Room

8. Ventilation And Heating
Satisfactory working conditions for staff ..
Good film handling and storage conditions..
Dark Room
Maintained by--
• Relative humidity 40-60%
• Room Temperature 18-20 °C

9. PASS-BOXES
NEEDED TO PASS
FILMS DIRECTLY
FROM THE X-RAY
ROOM TO
DARKROOM

11. Types of Entrance
Four designs of entrances
1. Single door system
2. Double door system
3. Labyrinth
4. Rotating door entrance
Dark Room

12. DARKROOM ENTRANCE:
SINGLE DOOR
Single door entrance
Access via single door only
Advantage:-
- Inexpensive.
- Less space used.
Disadvantages:-
- Not truly lightproof
- Poses safety hazard.

13. DARKROOM ENTRANCE:
DOUBLE DOOR
Two doors with small vestibule in between.
An electrical interlock can be fitted –one door cannot be opened until the other is closed

14. DARKROOM ENTRANCE:
MAZE / LABYRINTH

15. Labyrinth
• It has two parallel passages and a facing wall.
• Entire passage and walls are painted black.
• Length of passage 3 m
• Height of passage 2 m
• Each passage width 700 mm
• Emergency door
Advantages:-
Easy and instant accesses..
Continuous darkroom ventilation..
Disadvantage:-
Large amount off space occupied ..

16. DARKROOM ENTRANCE:
REVOLVING DOOR
Metallic cylinder with Advantages:
opening Less space is occupaied
at one end
for entry & exit.

17. DARKROOM LIGHT
SAFELIGHTS
WHITE LIGHTS

18. SafeLighting

19. SafeLighting
The word safe- as brief exposure will
not cause significant fogging
Functions
• Provide sufficient darkroom illumination
without any detrimental effect on the
sensitive film material.
• Helps for inspection of films during
processing.

20. Principle of operation
• X Ray film’s are color
sensitive- restricted to specfic
range of wavelength.
• Thus subjecting to non
sensitive wavelength and
cutting of white light.
SafeLighting

21. SafeLighting
Areas where safe light is required
• Film loading / unloading areas.
• Processor film feed-in points.
• Path b/w above two.
• At developer tank.

22. SafeLighting
Factors affecting safe lighting performance
• Safelight to film distance
• Bulb wattage
• Number and location of bulbs
• Film handling time:

23. Film handling time:
• the length of time the
film may be handled
in safelight condition
with out increase in
fog level.
• Its around 20 to 45sec.
SafeLighting

24. SafeLighting
Recommended standards
• Use only the recommended safelight filters
• Keep a required film light distance
• Keep minimum exposure to safelight s for
exposed as well as unexposed films

25. 7.5 W
FILM TRAY
15 W
4 feet
3 feet
25 W
1.2 M
SafeLighting

26. Required for
• Inspection & maintenance off cassettes & screens
• Cleaning purpose
• Servicing off equipment's
White light should be
• Close to ceiling
• Moderate intensity (60W tungsten or 30W fluorescent)
• Centrally placed
White lighting

27. FILM
PROCESSING…

28. Polyester Base..0.2 mm thick
Emulsion…Gelatin in silver hyalide crystal generally silver
iodobromide
Supercoat…Tranparent antistatic

29. LATENT IMAGE..
DEFINITION
MECHANISM OF FORMATION OF
LATENT IMAGE:
AgBr + X-ray photons = Ag+ + Br-
Silver bromide Silver ions Bromine ions
The latent image is formed by deposits of free (ionized) silver ions that
cannot be seen or
detected by any physical test devised as yet. It remains in the emulsion of
the X-ray film
until it is changed into a visible silver image by chemical processing
procedure

30. Film processing stages…
1.Devolopment
2.Wash ( stop bath )
3.Fixing
4.Final Washing
5. Dry

31. Processor Chemistry Overview
Developer – converts latent image into
manifest image
Stop bath -remove excess devolper
Fixer – clear the film of unexposed,
undeveloped silver bromide crystals,
promotes archival quality,image is now
stable and unaffected further by light.
Wash – rid the film of residual chemicals

33. (6 Ingredients)
1. Reducing Agent: reduce exposed silver halide to
black metallic silver
-Hydroquinone (Blacks)
-Phenidone (Grays)
2AgBr + Hydroquinone-----2Ag+quinone+2HBr
2. Activator: softens gelatin, maintains alkaline pH
(increase pH)
-Sodium Carbonate
Developer Solution

34. Developer Solution
3. Hardener: prevents damage to the
film from over swelling of gelatin
-Gluteraldehyde
4. Preservative: Antioxidant that
prevents oxidation of developer
-Sodium Sulfite

35. Developer Solution
5. Restrainer: prevents chemical fog
in new developer
-Potassium Bromide
6. Solvent: dissolves & ionizes the
developer chemicals
-Water

36. (5 Ingredients)
1. Clearing Agent: dissolves undeveloped
silver halide
- Thiosulfate ( HYPO )
2. Tanning Agent: shrinks, hardens,
preserves emulsion
-Aluminum Salt
Fixer Solution

37. Fixer Solution
3. Activator: neutralizes developer,
maintains acidic pH (decrease pH)
-Acetic Acid
4. Preservative: prevents oxidation,
prolongs solution life
-Sodium Sulfite
5. Solvent: dissolves other ingredients
-Water

38. Wash
 Rid the film of residual chemicals
 Residual chemicals on the film will discolor
radiograph over time.
 Cold water processors are less efficient in
removing chemicals – Warm water processors
much better.

39. (Not Washed Off)
Fixer Retention

40. AUTOMATIC DARKROOM
PROCESSORS

42. Thank you…